1. Field of the Invention
The present invention relates to an X-ray diagnostic apparatus in which a desired motion image corresponding to a static image can be easily obtained in an X-ray diagnosis, particularly, fluoroscopic or X-ray imaging, thereby improving accuracy of diagnosis.
2. Description of the Related Art
In a conventional X-ray diagnosis, a method is mainly used in which a doctor inspects an image (static image) obtained by X-ray film imaging. Also, a motion image (hereinafter called as "fluoroscopic image") using an image intensifier-TV system is inspected in addition to the inspection of the static image as required. Generally, since the X-ray image is obtained by radiating an X-ray having high energy on an object to be examined for a short period of time, an image having high contrast can be obtained. On the other hand, since such a three-dimensional object to be examined is expressed by a two-dimensional image, there is a drawback in that the depth of the object cannot be easily examined. In the fluoroscopic image, since it is required that the X-ray be radiated on the object to be examined for a long period of time, energy of the X-ray must be low. Due to this, the obtained image has a large amount of noise with low contrast. On the other hand, in the fluoroscopic image, there is an advantage that the depth of the three-dimensional object can be easily examined.
In recent years, there has been studied an imaging method using no X-ray film, for example, a method (digital imaging) in which an X-ray having high energy is radiated on the object to be examined for a short period of time and the object is imaged as an electrical signal by use of a solid imaging device such as a CCD. Then, there has been used a diagnostic method in which the fluoroscopic image or the X-ray image is recorded in a recording medium, which is on the market, such as a video tape recorder (VTR) or a video disk recorder, and the image is reproduced for diagnosis. However, the doctor can neither easily retrieve a desired image nor reproduce the image.
As mentioned above, in the prior art, there is difficulty in judging abnormality. Moreover, in the diagnostic method, which has come into wide use recently, the doctor cannot easily reproduce a desired image.